Southern California -- this just in

Link sought between Sylmar explosion and Simi Valley blast

Authorities said they were looking for connections between an explosion at a Sylmar alternative energy company this week and a deadly explosion last year at a Simi Valley firm owned by the same man.

The blast Tuesday in Sylmar tore a hole in the roof and shattered windows of neighboring businesses. Timothy Larson, a veteran Los Angeles city firefighter who has been on disability leave for several years, was critically injured. Another employee was also injured.

On June 17, 2010, an explosion at a Simi Valley alternative energy company blew off part of the roof and caused parts of the building to collapse. Employee Tyson Larson, 28, was killed and two others injured.

Both firms are owned by Timothy A. Larson, the father of the two men.

The Simi Valley blast resulted in three citations totaling more than $5,600 after a California Division of Occupational Safety and Health investigation. Investigators said the company had used an air compressor and two pressure vessel tanks that it was not permitted to use, and that it used altered tanks in a way that were not "good engineering practice" and "not in accordance with" national standards.

The company was in the process of appealing the citations. Tuesday's explosion occurred while workers were transferring hydrogen gas from one cylinder to another, said Erika Monterroza, a spokeswoman for the California Department of Industrial Relations. Fire officials said the company was in the business of extracting hydrogen from water to create an alternative-fuel source.